Assignment task: The Lake Superior watershed is unusual in that the lake part is about 39% of the entire watershed area (81,000 mi2 = 2.26(1012) ft2). This makes a water budget a little different in that the lake part is only evaporation (E) and the landscape part experiences evapotranspiration (ET). Average annual precipitation across the basin is about 31 inches/yr, although it varies significantly in different parts, especially west to east. Lake evaporation is about 36% of precipitation. Land-based evapotranspiration is 61% of precipitation. Ignoring the rather small amount of diversion into L. Superior that occurs in Canada (i.e., no surface or groundwater inflows into the basin), estimate the average annual outflow at the St. Mary's River (the only outflow) in ft3/s (cfs). Remember to convert years to seconds (31,536,000 s = 1 yr). Correct answers will be approximately in the 60,000-120,000 cfs range. Helpful hint in the calculations: there are a lot of big numbers in this, so if you combine the ones (areas) with unit conversions (years to seconds and inches to feet) at the start, you can work with somewhat smaller numbers and fewer calculation steps).